The present invention relates to orthodontic arch wires and, more particularly, to a method for producing a braided orthodontic arch wire exhibiting substantially constant force over a range of deflection, and to the arch wire produced thereby.
In orthodontic assemblies, generally the practitioner places tooth bands and brackets upon the maloccluded teeth and then forms an arch wire about the brackets to produce a desired force in the direction in which the tooth is to be moved. Desirably, such arch wires will exhibit a level of force sufficient to effect the correction over a period of time without producing too great a discomfort for the patient. In addition, the arch wires should recover from the deflection which is produced for the initial assembly so as to avoid taking a permanent set, i.e., be resiliently deformable within the range required for the installation.
Both single strands and multistrand braids have been used in the fabrication of arch wires. In some instances, the arch wires have also been formed by coiled strands depending upon the alloy employed and the forces desired.
As is known, multiple strand braids offer advantages over single strands. Moreover, it is desirable to use an arch wire with a rectangular cross section to facilitate engagement by the tools and in the brackets.
Exemplary of efforts to produce suitable arch wires are the structures shown in Paugh et al. U.S. Pat. No. 3,838,515, Baues et al. U.S. Pat. No. 3,729,824, Andreason U.S. Pat. No. 4,037,324 and Wallshein U.S. Reissue Pat. Nos. RE. 30,332 and RE. 30,593.
In addition to the desired properties of relatively constant force and a high degree of resilient deformation, the arch wire must be one which can be easily manipulated by the orthodontist, be inert in the patients mouth and be one which can be readily formed into the desired arcuate configuration.
It is an object of the present invention to provide a novel method for fabricating orthodontic arch wires which exhibit relatively constant force over a substantial range of deflection and excellent resilient deformability.
It is also an object to provide such a method which may be easily and economically practiced to produce such arch wires in the desired curvature.
Still another object is to provide a novel braided arch wire of rectangular cross section exhibiting substantially constant force over a relatively broad range of deflection and which will resiliently recover from substantial deformation.